Safety paper and method of forming the same



Patented Apr.\2. 8, 19 25. I

UNITED STATES P TENT OFFICE.

CHARLES minim SAMME'I", or Damon, MASSACHUSETTS, hssrenon TO CRANE &

COMPANY,OF DALTON, MASSAQHUSETTS, A raarunasmr.

SAFETY PAIER AND METHOD OF FORMING THE SAME.

No Drawing.

To all whom it may concern:

Be it known "that I, CHARLES FRANK SAMMET, a citizen of the United States, re-

siding at Dalton, in the county of Berkshire,

' State of Massachusetts, have invented certain newand useful Improvements in Safety As set forth in applications executed of 20 even date herewith (Ser. Nos. 511.808 and 511,809), I have discovered that substances of the benzidine group, that is, primary amines such as benzidin'e, tolidin and dianisidine; and diphenylamin; and various derivatives thereof which have the benzidine nucleus and the primary amine radical therein, and diphenylamin when incorporated with paper impart to such paper the quality of being permanently stained by chemical ink eradicators which generally include oxidizing agents having the property of producing this stain although other ingredients of the eradicator may have a somewhat similar eflect'.

I have described and claimed in said other applications the product produced by the application of these ingredientsthat is, the safety paper and also the process of making the same with the proportions ofingredients used.

As a further development of this line of invention, I have discovered that good results can be accomplished-that is, as to making the paper safe from change, that is to say any writing or mark made upon such paper cannot be bleached out without giving an indication that an attempt to eradicate the writing or other mark thereon has been made, by forming the substances or ingredient to be used for that purpose, such as benzidine, diphenylamin, or the insoluble Application filed October 31, 1921. Serial No. 511,810.

salts thereof, in stick form ,by molding, or by any suitable means preferably with the addition of a small amount of binding agent, such as starch paste, in suficient quantity to make the particles of the ingredients co-here in a solid mass.

I, therefore, intend in this application for patent to include not only the productrtl1at 1s, paper made by applying to .it when finished by rubbing or sprinkling, or in any other way, the ingredient to the external face of the paper, but also desire to claim as an article of manufacture the ingredient used for the purpose when molded or formed into stick form convenient for the purpose.

When it is desired to make any paper or document safe against chemical erasure all that is necessary to do is to rub said stick over either the whole surface of the paper or document or that portion of it which it is most desired to make safe against chemical erasure,'and then by blowing or dusting remove any surplus material adhering to the surface of the paper; Such application of the stick may be made either before writing or printing or otherwise marking upon the surface of the'paper, or

thereafter, it being essential only that the surface of the paper have some of the maso terial remaining thereon and that suflicient remains thereon permanently to efiect the desired purpose. As heretofore stated, this stick may be composed of benzidine, or its homologues; diphenylamin, or its homologues; or, instead of being in stick form, either of these ingredients may be sprinkled or dusted on, and then rubbed in in any, suitable man By the expression benzidine material as used in the appended claims, I mean to include colorless primary amines. such as benzidine, tolidine, dianisidine, etc., that is, substances which are closely related to benzidine when incorporated with paper, or the colorless salts thereof, such compounds having the double ring nucleus and primary amine groups therei Having thus described my inventiomwhat I claim as new and desire to secure by Letters Patent of the United States is:

5. The process of making paper safe against chemical erasure which comprises the application to the surface thereof of a material including a salt of benzidine.

6. The process of making paper safe against chemical erasure which comprises the application to the surface thereof of a material including an insoluble salt of benzidine.

In testimony whereof, I afiix my signature.

CHARLES FRANK SAMMET. 

